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REPORT   ON   THE 

GEOLOGICAL   EXCURSION    THROUGH 
NEW   MEXICO,   ARIZONA,  AND   UTAH 

SUMMER   OF    1906 


BY   DOUGLAS    WILSON  JOHNSON. 


[Reprinted  from  TECHNOLOGY  QUARTERLY,  Vol.- XIX,  No.  4, 
December,  1906] 


408  Report  on  tJie  Geological  Excursion 


CONTRIBUTION  FROM  THE  DEPARTMENT  OF  GEOLOGY 

REPORT  ON  THE  GEOLOGICAL  EXCURSION  THROUGH 

NEW  MEXICO,  ARIZONA,  AND  UTAH, 

SUMMER  OF    1906 

BY   DOUGLAS    WILSON   JOHNSON 

IN  connection  with  the  study  of  certain  problems  in  physiographic 
^f    geology,  and  for  the  purpose  of  supplying  certain  deficiencies  in  our 

•  teaching  collection   in   that  subject,   I   some  time  ago  formulated  the 

•  plans  for  a  wagon  trip  through  some  of  the  more  inaccessible  parts  of 
the  Southwest.     It  seemed  to  me  that  such  a  trip  would  make  possible 

Q  the  collection  of  data  which  might  solve,  or  at  least  make  desirable 
trt  contributions  to,  some  of  the  problems  in  connection  with  the  history 
<;  of  the  plateau  province  of  Arizona  and  Utah,  the  origin  of  the  volcanic 
25  buttes  in  the  'Mount  Taylor  district,  New  Mexico,  and  the  character 
•jg  and  origin  of  the  Basin  Ranges  of  Utah  ;  also  the  collection  of  valuable 
.  illustrative  material  for  the  courses  in  topographic,  lithologic,  and  pale- 
£Z  ontologic  geology.  The  execution  of  the  plans  for  such  an  excursion 
3E  was  made  possible  last  spring  by  an  award  of  $250  from  the  Austin 
*^  Fund,  a  grant  of  similar  amount  from  the  Sturgis-Hooper  Fund  of 
^  Harvard  University,  and  by  private  gifts  from  friends  of  the  Institute 
amounting  to  $500. 

Dr.  H.  W.  Shinier,  of  the  Institute  Geological  Department,  and 
Mr.  C.  H.  Decker,  a  graduate  of  the  Columbia  University  School  of 
Mines,  looked  after  the  stratigraphic  and  economic  geological  problems 
more  particularly,  Dr.  Shimer  securing  much  material  which  will  add 
greatly  to  the  value  of  the  Institute's  teaching  collections,  and  which 
will  form  the  basis  of  future  publications.  The  main  energies  of  the 
party,  however,  were  directed  to  the  study  of  problems  and  the 
collection  of  material  which  were  related  to  physiographic  geology. 
The  party  left  Albuquerque,  central  New  Mexico,  on  the  3ist  day 
of  May,  with  camp  outfit  and  provisions  for  a  ten  days'  trip  in  the 


(o 


Douglas    Wilson  Johnson  409 

Mount  Taylor  district.  This  region  was  made  classic  by  the  report 
of  Major  C.  E.  Button  on  the  volcanic  necks  and  other  volcanic  fea- 
tures there  represented.  These  necks  were  described  as  showing 
vertical  columnar  structure  in  many  cases,  being  of  enormous  size  and 
nearly  cylindrical  in  shape  or  somewhat  elongated  in  one  direction, 
while  the  adjacent  sedimentary  beds  were  not  much  disturbed.  In 
recent  years  some  doubt  had  been  expressed  as  to  the  interpretation 
of  these  features,  it  being  argued  that  vertical  columnar  structure 
should  not  be  expected  as  a  prominent  feature  in  volcanic  necks,  but 
was  rather  indicative  of  some  other  origin  for  the  famous  buttes ;  that 
it  was  difficult  to  understand  how  a  cylindrical  neck  or  plug  could  be 
forced  up  through  sedimentary  beds,  especially  if  those  beds  were  not 
profoundly  disturbed.  Professor  Jaggar  has  concluded  that -the  Mato 
Tepee,  or  Devil's  Tower,  of  Wyoming  (fully  described  in  his  report  on 
the  geology  of  the  Black  Hills),  a  butte  which  bears  a  striking  resem- 
blance to  some  of  the  New  Mexico  types,  must  be  the  remnant  of  an 
old  laccolith,  basing  his  conclusion  on  the  vertical  columnar  structure, 
the  undisturbed  sediments  at  the  base  of  the  tower,  and  the  association 
of  the  butte  with  undoubted  laccoliths  still  well  preserved. 

It  was  in  the  hope  of  securing  data  bearing  on.  this  problem  that 
we  examined  a  number  of  the  finest  examples  of  the  buttes  in  the 
Mount  Taylor  district.  The  study  led  to  the  following  conclusions  : 

(1)  The  buttes   are   undoubted  volcanic  necks   of   large  size,   one  of 
them    rising  over   2,000  feet   above   the    surrounding   valley   lowland. 

(2)  Many  of  them  show  good  columnar  structure  more  or  less  nearly 
vertical ;  it   is  believed  that   this  position  is  due  to  the  floor  of  the 
crater's  acting   as    the  cooling  surface  for  the  upper   portion  of   the 
neck,  at  least,  rather  than  the  probably  heated  walls  of  the  conduit  up 
through  which  the  lava  came ;  the  columns  developing  at  right  angles 
to  the  cooling  surface  would  thus  be  vertical,  instead  of  radial  or  irreg- 
ular, as  formerly  supposed.     (3)  The  necks  are  more  or  less  cylindrical 
in  shape,  and  have  come  up  from  unknown  depths  without  in  the  least 
disturbing  the  surrounding  sediments  in  most  cases,  thus  showing  that 
enormous  plugs  may  force  a  clean  passage  through  sedimentary  rocks, 
however  difficult  the  process  may  be  of  explanation      (4)  The  age  of 
the  rocks,  the  general  geology  and  physiography  of  the  region,  and  the 
detailed  character  of  the  necks  were  studied.     Typical  rock  specimens, 
fossils,   and  photographic  views  were  obtained.      The  results  of  this 
study  will  be  published  during  the  year  under  the  title,  "  The  Volcanic 
Necks  of  the  Mount  Taylor  Region,  New  Mexico." 


4IO  Report  on  the  Geological  Excursion 

After  returning  to  Albuquerque,  our  party  went  by  rail  to  the 
Big  Bug  mining  district,  some  twenty-five  miles  southeast  of  Prescott, 
Arizona,  where  we  made  our  headquarters  in  the  northern  end  of  the 
Bradshaw  Mountains  while  outfitting  for  the  trip  across  the  deserts 
to  the  north.  We  experienced  considerable  difficulty  in  securing  suit- 
able horses  and  wagons,  but  after  some  delay  procured  an  outfit  of  five 
horses,  two  wagons,  the  necessary  saddles,  tent,  bedding,  provisions, 
etc.,  and  on  the  iQth  of  June  started  northward.  We  soon  turned 
eastward  to  the  valley  of  the  Verde  River,  making  a  study  of  the 
large  limestone  series  of  that  district  with  a  view  to  determining  its 
age  and  origin.  Thence  turning  northeast  we  followed  up  Oak  Creek 
to  the  foot  of  the  great  Mogollon  escarpment,  which  terminates  the 
plateau  district  on  the  south,  and  after  a  few  miles  of  the  steepest 
and  roughest  road  encountered  during  the  whole  summer  reached  the 
summit,  where  we  could  look  far  to  the  northward  and  see  the  San 
Francisco  Mountain  rising  high  above  the  surrounding  forest-covered 
plateau  surface,  while  below  us  to  the  south  lay  the  arid  lands  of 
the  basin  region.  Here  we  were  able  to  trace  the  relations  of  several 
great  faults  which  help  to  determine  the  rectangular  pattern  of  the 
southern  margin  of  the  plateau  in  this  region.  Continuing  northward 
to  Flagstaff,  we  found  extensive  lava  flows  covering  portions  of  the 
plateau  which  do  not  appear  on  the  previous  maps  of  the  region. 
From  Flagstaff  we  turned  southeast  to  Walnut  Canyon,  the  region  of 
some  of  the  best  cliff-dwellings  in  the  Southwest.  Dr.  Shimer  made 
a  detailed  study  of  the  geological  section  exposed  in  the  canyon  walls, 
collecting  a  series  of  characteristic  fossils  and  determining  the  char- 
acter of  the  beds  which  weather  into  overhanging  ledges  and  thus 
afford  the  conditions  utilized  by  the  cliff-dwellers  in  making  their 
homes. 

We  next  passed  around  the  western  base  of  the  San  Francisco 
Mountain,  and  established  a  camp  well  up  the  northwest  slope.  From 
this  camp  we  made  a  two  days'  trip  with  pack  outfit  to  the  summit 
of  the  old  volcano  to  study  the  effect  of  ancient  glaciation  at  the  high- 
est levels.  Although  so  far  south,  the  peak  rises  to  such  an  altitude 
(12,794  feet  above  sea  level)  that  its  summit  was  occupied  by  a  local 
glacier  during  the  glacial  period,  this  glacier  eroding  a  splendid  cirque 
in  the  very  centre  of  the  volcano,  and  leaving  a  prominent  terminal 
moraine  a  short  distance  down  the  valley  into  which  the  cirque  opens. 
Even  today  the  snows  lie  on  the  higher  levels  and  in  sheltered  places 


Douglas    Wilson  Johnson  411 

until  well  into  the  summer,  our  camp  on  the  night  of  July  6  being 
pitched  between  two  snowdrifts  over  10  feet  high.  Five  days  later  we 
were  in  the  bottom  of  the  Grand  Canyon,  10,000  feet  lower,  our  party 
almost  prostrated  by  the  intense  heat. 

From  the  San  Francisco  volcano  we  went  to  a  point  near  Grand 
View  on  the  rim  of  the  Grand  Canyon  of  the  Colorado,  where  we 
established  a  camp  for  several  days.  After  visiting  several  points  on 
the  rim  of  the  canyon,  we  descended  the  old  abandoned  Red  Canyon 
trail,  spending  two  nights  and  parts  of  three  days  in  the  Grand  Can- 
yon, returning  to  the  summit  of  the  plateau  by  the  Grand  View  trail. 
We  then  returned  to  the  northern  side  of  the  San  Francisco  group, 
where  we  investigated  a  recent  cinder  cone  and  lava  flow,  so  recent, 
in  fact,  that  erosion  has  as  yet  produced  no  effect  on  either  cone  or 
flow,  both  being  perfectly  formed,  dense  black  in  color,  and  fairly  free 
from  soil  or  vegetation.  Studies  were  made  also  of  numerous  other 
cones  and  flows  throughout  the  plateau  region,  resulting  in  the  estab- 
lishment of  the  fact  that  the  so-called  "period  of  basalt  outflow"  is 
really  divisible  into  at  least  five  or  six  different  periods,  with  long  ero- 
sion intervals  between  them.  Collections  of  fossils  and  rock  specimens 
from  the  Grand  Canyon  and  other  parts  of  this  district  were  made. 

Crossing  eastward  to  the  Little  Colorado  River,  and  then  northward 
to  the  trading  post  at  Tuba,  we  secured  our  last  supply  of  grain  and 
provisions  before  entering  on  the  most  strenuous  part  of  our  journey, 
the  crossing  of  the  Painted  Desert.  Already  we  had  suffered  some 
difficulty  in  securing  water  fit  to  drink  and  sufficient  grass  for  the 
horses.  At  Tuba  we  were  disappointed  to  find  no  grain,  except  a  little 
Indian  corn,  which  the  horses  did  not  seem  to  regard  with  favor.  With 
little  prospect  of  grass  on  the  desert,  the  outlook  was  discouraging. 
The  weather  was  now  intensely  hot,  so  that  we  found  it  advisable  to 
travel  mainly  at  night,  resting  during  the  day.  Accordingly  we  usually 
arose  about  three  or  four  in  the  morning,  drove  until  the  heat  became 
oppressive,  rested  until  six  in  the  evening,  then  drove  until  well  into 
the  night,  or  until  we  lost  our  way  in  the  darkness.  During  the 
middle  of  the  day  we  erected  a  canvas  awning  to  protect  ourselves 
from  the  sun,  but  even  in  the  shade  thus  afforded  our  thermometer 
registered  115°  and  we  found  it  difficult  to  sleep. 

We  secured  good  water  at  Willow  Springs,  a  short  distance  from 
Tuba,  and  began  the  journey  northward  along  the  western  base  of  the 
Echo  Cliffs.  These  cliffs  are  produced  by  erosion  on  an  eastward 


412  Report  on  the   Geological  Excursion 

dipping  monocline  of  sandstone,  but  have  a  much  sharper  form  and 
steeper  back  slope  than  would  appear  normal  for  the  gentle  monoclinal 
dip.  This  sharpness  of  form  had  been  noted  by  Professor  Davis,  of 
Harvard  University,  on  an  excursion  some  years  before,  and  tentatively 
ascribed  to  possible  faulting  along  the  back  slope  of  the  monocline. 
Several  traverses  across  the  monocline  at  critical  points  showed  the 
absence  of  any  such  faults,  but  revealed  the  fact  that  cross  bedding 
at  high  angles  and  with  rather  uniform  eastward  dip  caused  the  rocks 
to  weather  with  steep  eastward  slopes,  thus  determining  the  peculiar 
topographic  feature  observed  in  the  cliffs.  Numerous  landslides  on 
a  large  scale  were  observed,  thus  confirming  the  previous  observations 
of  Professor  Davis  regarding  the  recent  revival  of  erosion  in  the  Grand 
Canyon  region,  with  consequent  undermining  of  previously  graded  slopes, 
causing  extensive  landslides  in  the  areas  near  the  revived  streams. 

By  the  time  we  reached  the  crossing  of  the  Colorado  River  at  Lee's 
Ferry,  near  the  Utah  line,  our  horses  were  pretty  well  exhausted, 
owing  to  the  hot  weather,  lack  of  grain,  sandy  roads,  and  scarcity  of 
grass,  good  grass  being  found  at  only  two  points  along  the  road  from 
Tuba.  At  Lee's  Ferry  we  had  counted  on  obtaining  grain,  but  were 
greatly  chagrined  to  find  that  the  supply  on  hand  at  that  point  had 
been  nearly  consumed,  so  that  the  best  we  could  do  was  to  secure 
twenty-five  pounds  of  oats,  this  to  last  five  horses  for  over  one  hundred 
miles  of  desert  and  mountain  roads ! 

Ten  miles  beyond  the  ferry  we  found  ourselves  facing  a  serious 
problem.  The  horses  first  stumbled  repeatedly,  then  stopped  short 
and  refused  to  go  another  step.  There  was  no  grass,  and  it  required 
a  hunt  of  several  hours  to  find  a  little  pool  of  salty  water  and  get  the 
horses  to  it,  after  having  first  taken  them  out  of  the  harness  and  let 
them  rest.  That  evening  we  succeeded  in  getting  them  a  little  farther, 
but  found  no  grass  or  water.  The  next  morning  we  managed  to  reach 
good  water  and  a  little  grass.  Here  it  became  necessary  to  leave  one 
horse  and  one  of  the  wagons  behind  and  pull  the  other  wagon  by  means 
of  four  horses.  Walking  ourselves,  we  were  thus  able  to  make  about 
twelve  miles,  over  very  sandy  roads  and  under  an  intensely  hot  sun. 
Returning  with  the  horses  the  second  day,  the  other  horse  and  wagon 
were  brought  up,  this  method  being  persisted  in  until  the  foot  of  the 
Kaibab  plateau  on  the  western  side  of  the  desert  was  reached,  an 
average  advance  of  about  six  miles  a  day  being  made.  After  a  short 
rest  at  a  spring  at  the  foot  of  the  Kaibab,  the  horses  were  able  to 


Douglas    Wilson  JoJmson  413 

pull  the  wagons,  one  at  a  time,  up  to  the  higher  country  on  the  summit, 
where  we  found  better  grass.  The  Kaibab  plateau  and  the  Kanab 
desert  were  crossed  with  less  difficulty,  although  the  long  delay  had 
so  far  exhausted  our  own  store  of  provisions  that  the  members  of  the 
party  had  to  get  along  with  scanty  rations  the  last  four  days  before 
reaching  a  new  base  of  supplies. 

In  spite  of  the  difficulties  encountered  this  part  of  the  trip  was 
most  profitable.  We  were  able  to  make  a  study  of  the  streams  which 
are  dissecting  the  east  Kaibab  monocline,  and  to  discover  marked  dif- 
ferences between  the  lower  and  upper  courses  of  the  streams,  indicating 
two  distinct  erosion  periods  in  the  development  of  the  region.  This 
conclusion  was  confirmed  by  the  study  of  certain  terraces  discovered 
farther  south  along  the  monocline  and  by  a  consideration  of  the  rela- 
tion of  one  of  the  larger  valleys  to  the  monocline,  all  of  which  features 
offer  strong  evidence  in  favor  of  the  recently  proposed  theory  that 
the  faults  and  folds  of  the  plateau  province  are  much  older  than  the 
present  Colorado  River,  as  opposed  to  the  former  belief  that  the  river's 
course  was  first  established  and  that  the  faults  and  folds  are  of  later 
development. 

From  Kanab,  in  southern  Utah,  our  party  went  north  to  Upper 
Kanab  to  study  the  terraces  which  terminate  the  high  plateaus  on  the 
south.  The  Tertiary  beds,  forming  the  highest  part  of  this  series, 
have  been  considered  of  lacustrine  origin  until  late  years,  when  the 
possibility  of  a  subaerial  origin  has  been  entertained  by  some  observers. 
We  secured  evidence,  both  here  and  farther  north,  strongly  indicating 
a  subaerial  origin.  The  origin  of  the  Triassic  and  Jurassic  beds  are 
also  in  doubt,  and  we  made  some  studies  as  to  detailed  structures  which 
we  hope  will  aid  in  solving  this  problem.  Collections  of  the  rather 
scarce  Jurassic  fossils  were  made,  and  some  points  of  interest  regarding 
lava  flows  in  the  valleys  noted. 

Returning  to  Kanab,  we  then  went  southward  across  the  Uinkaret 
desert  to  the  lower  portion  of  the  Toroweap  valley  near  the  Grand 
Canyon.  This  region  was  of  special  interest,  as  offering  undoubted 
evidence  as  to  the  age  of  two  of  the  great  faults  of  the  plateau  province. 
The  region  being  difficult  of  access  on  account  of  the  scarcity  of  water, 
evidence  believed  to  be  available  had  not  yet  been  secured,  and  to 
supply  this  lack  we  attempted  the  trip.  Dutton  reported  that  all  of 
the  faults  of  this  region  were  topographically  recent,  that  wherever  the 
faults  were  present  cliffs  of  the  upthrow  side  overlooked  the  lower 


414  Report  on  fhe  Geological  Excursion 

downthrow  side,  and  that  the  Sevier  and  Toroweap  faults  in  this  spe- 
cial district  were  separate  and  distinct.  Professor  Davis  has  recently 
advanced  the  theory  that  the  faults  are  much  more  ancient,  so  ancient, 
in  fact,  that  erosion  has  once  obliterated  the  topographic  effects  of 
faulting  by  leveling  off  the  country ;  while  recent  erosion,  removing 
the  soft  beds,  has  caused  the  reappearance  of  fault  line  cliffs  wherever 
the  old  faulting  brought  hard  and  soft  beds  opposite  each  other,  the 
cliffs  thus  facing  toward  the  upthrow  in  some  cases,  toward  the  down- 
throw in  others.  Thus  it  was  shown  that  the  cliffs  of  today  are  often 
located  on  the  side  where  the  lowland  was  originally  found,  while  the 
lowland  of  today  has  been  worn  out  of  the  rocks  which  were  faulted 
up,  reversing  the  original  topographic  effects  of  faulting.  Professor 
Davis  further  believed  that  the  Sevier  and  Toroweap  faults  were 
continuous,  being  one  and  the  same. 

A  somewhat  detailed  study  of  the.  region  in  question  enables  us 
to  add  a  considerable  amount  of  evidence  which  strongly  corroborates 
the  theory  of  a  very  great  age  for  the  faults,  and  which  makes  the 
theory  of  recent  faulting  wholly  inadmissible.  A  traverse  of  some  of 
the  more  inaccessible  parts  of  the  region,  however,  showed  that  the 
two  faults  were  quite  distinct,  overlapping  each  other  for  many  miles, 
but  the  Toroweap  being  from  six  to  fifteen  miles  or  more  west  of  the 
southern  extremity  of  the  Sevier.  The  age  of  a  part  of  the  rock  series 
of  this  region  is  in  doubt  because  of  the  scarcity  of  fossil  remains.  We 
were  fortunate  in  securing  some  fossils  from  the  doubtful  strata,  which 
we  hope  will  serve  to  establish  their  age  more  definitely. 

After  returning  from  the  Toroweap  country  we  went  westward  to 
the  Hurricane  fault,  and  spent  several  days  in  camp  on  the  bank  of  the 
Virgin  River,  waiting  until  one  of  the  greatest  floods  in  the  river's 
history  should  subside  sufficiently  to  enable  us  to  ford.  This  enforced 
delay  gave  time  for  a  careful  study  of  the  features  of  the  fault  scarp 
for  several  miles  south  of  the  river.  This  region  has  been  described 
in  some  detail  by  Messrs.  Huntington  and  Goldthwait  in  an  admirable 
paper.  They  established  the  occurrence  of  two  distinct  periods  of 
faulting  along  the  great  fracture  with  an  intervening  erosion  period. 
A  careful  study  of  the  relation  of  certain  lava  flows  to  the  fault  enabled 
us  to  discover  a  third  period  of  movement  or  faulting  quite  as  distinct 
as  the  two  previously  noted,  with  long  time  intervals  separating  it  from 
those  other  periods.  The  relation  of  a  number  of  successive  lava  flows 
and  their  effect  on  the  former  topography  were  worked  out. 


Douglas    Wilson  Johnson  415 

Northward  from  the  Virgin  our  course  lay  along  the  foot  of  the 
western  rim  of  the  high  plateaus  on  the  eastern  border  of  the  Great 
Basin  region.  We  traced  the  Hurricane  fault  for  a  hundred  miles  or 
more  to  the  northward,  studying  the  details  of  the  faulting  in  many 
different  localities.  Recent  faulting  was  discovered  along  the  western 
side  of  Round  Valley ;  the  stratigraphic  series  of  that  region  was  found 
to  be  quite  unlike  the  representations  on  earlier  maps,  and  the  region 
was  remapped  as  far  as  practicable.  Some  fossils  were  collected  from 
the  more  recent  members  of  the  series.  Collections  of  rhyolite,  tra- 
chyte, and  andesite  from  type  localities  were  made  for  the  purpose  of 
supplementing  the  Institute  study  series.  The  character  of  the  Tertiary 
beds  in  several  regions  was  studied  with  regard  to  the  question  of  their 
origin,  and  numerous  observations  of  miscellaneous  geological  features 
were  noted. 

As  we  neared  the  Salt  Lake  City  region  we  had  opportunity  to 
observe  the  topographic  features  of  the  ancient  shore  lines  of  the 
former  Lake  Bonneville,  type  examples  of  dissected  fault  block  moun- 
tains, and  other  features  which  have  made  this  classic  ground  for  all 
students  of  geology.  The  numerous  photographs  and  sketches  that 
were  made  of  these  typical  features  will  add  much  to  the  effectiveness 
of  the  courses  in  topographic  geology. 

In  the  villages  and  towns  just  south  of  Salt  Lake  City  the  outfit 
was  disposed  of  and  the  party  disbanded.  Dr.  Shimer  went  to  the 
Yellowstone  National  Park  for  a  short  trip,  Mr.  Decker  to  the  Bingham 
mining  district,  while  I  returned  east  by  way  of  Butte,  Montana. 

It  will  be  seen  that  the  results  of  the  expedition  include  the  col- 
lection of  data  bearing  on  a  number  of  special  problems  of  some 
scientific  importance,  as  well  as  a  variety  of  miscellaneous  observations 
which  should  be  permanently  recorded.  It  is  proposed  to  publish  dis- 
'  cussions  of  the  larger  problems  as  separate  reports  during  the  coming 
year  in  different  geological  journals,  and  the  miscellaneous  observations, 
together  with  a  brief  abstract  of  the  larger  problems,  as  one  report. 

Our  party  was  in  the  field  nearly  four  months,  traveling  over  fifteen 
hundred  miles  by  wagon  and  probably  at  least  three  hundred  more  on 
horseback. 

*  £  O     Vwwc..  ,y  <KU.£.^   £u   '"kfcty 


